The temperature is effected because when the earth rotates, it is on a tilt. That tilt never changes but during orbit, the hemisphere that faces the sun does. In the summer, the northern hemisphere is tilted more towards the sun so they receive more direct sunlight and the southern hemisphere receives less. In the winter, the southern hemisphere is tilted toward the sun and receives more direct sunlight therefore, the temperature is effected by the tilt of the earth.
